(NASA) – Two astronauts will venture outside their spacecraft today in the first of three planned spacewalks for the mission. They will install back-up communications equipment onto the station and a work platform onto a station robot.

Mission Specialists Garrett Reisman and Stephen Bowen spent the night in the Quest Airlock to prepare for the planned 6.5-hour spacewalk. They are expected to egress from the airlock at 8:15 a.m. EDT. Good and Expedition 23 Flight Engineer T.J. Creamer will help with the suit-up preparations, and Good will join Pilot Tony Antonelli, the intravehicular officer, to assist during the spacewalk. Mission Specialist Piers Sellers and Flight Engineer Tracy Caldwell Dyson will support robotic arm operations throughout.

Space shuttle Atlantis is photographed from the International Space Station prior to docking. Image credit: NASA

The first task of the spacewalk will be the installation of a back-up Ku-band antenna known as the SGAnt or Space-to-Ground Antenna. The task will start at the mobile transporter to remove the SGAnt, then Reisman will hand carry the boom and antenna to its installation point on the Z1 truss. Bowen will meet Reisman there to attach the antenna, connect power and data cables and remove protective insulation. During that time, Reisman will travel on the arm to retrieve the antenna dish and bring it to the worksite for installation. Time permitting, Bowen will install a heat shield and remove position locks on the antenna.

Reisman will again return to the pallet to collect Dextre’s storage platform. He and Bowen will meet at Dextre’s worksite atop the Destiny laboratory to attach the platform to the robot. If possible, they will also install a maintenance tether and connect two electrical fuses.

The final task will have Bowen at the end of the left or port truss, to loosen bolts on the six batteries that will be replaced in the later spacewalks.

Throughout the extravehicular activity, Commander Ken Ham will oversee the activities and work on transfer of supplies to the station.